Table 6. Multivariable Cox proportional hazards regression models for 30-day mortality of patients with HAP.

Variables		Unadjusted HR (95% CI)	P value	Adjusted HR (95% CI)	P value
Propensity score-matched overall patientsa
	Monotherapy	1 (ref.)		1 (ref.)
	Combination therapy	0.990 (0.672–1.460)	0.960	1.646 (0.782–3.461)	0.189
Microbiologically documented patientsb
	Monotherapy	1 (ref.)		1 (ref.)
	Combination therapy	1.176 (0.640–2.159)	0.602	1.594 (0.803–3.165)	0.182
Clinically documented patientsc
	Monotherapy	1 (ref.)		1 (ref.)
	Combination therapy	0.825 (0.493–1.383)	0.466	0.849 (0.490–1.472)	0.561

HAP = hospital-acquired pneumonia, HR = hazard ratio, CI = confidence interval, CCI = Charlson Comorbidity Index, CFS = Clinical Frailty Scale, SOFA = Sequential Organ Failure Assessment, VAP = ventilator-associated pneumonia.

^aAdjusted for age, sex (male), chronic neurological disease, CCI, CFS, SOFA score, classification of infection, prior antibiotic use within 90 days, risk of aspiration, late-onset HAP, VAP, combination with glycopeptides, mechanical ventilation, renal replacement therapy, A. baumannii, Enterobacteriaceae, and P. aeruginosa.

^bAdjusted for age, sex (male), chronic neurological disease, CCI, CFS, SOFA score, prior antibiotic use within 90 days, aspiration risk, late-onset HAP, VAP, combination with glycopeptides, mechanical ventilation, renal replacement therapy, A. baumannii, Enterobacteriaceae, and P. aeruginosa.

^cAdjusted for age, sex (male), chronic neurological disease, CCI, CFS, SOFA score, prior antibiotic use within 90 days, aspiration risk, late-onset HAP, VAP, combination with glycopeptides, mechanical ventilation, and renal replacement therapy.